BEIRUT - Powerful explosions struck the outskirts of Damascus early on Sunday, sending columns of fire into the night sky, and Syrian state television said Israeli rockets had struck a military facility just north of the capital.

Israel declined to comment on the attack, but the blasts occurred a day after an Israeli official said his country had carried out an air strike targeting a consignment of missiles in Syria intended for the Lebanese militant group Hezbollah.

One of the sites hit on Sunday, the Jamraya military research centre, was also targeted by Israel in January.

“The new Israeli attack is an attempt to raise the morale of the terrorist groups which have been reeling from strikes by our noble army,” Syrian television said, referring to recent offensives by President Bashar al-Assad’s forces against rebels.

The British-based Syrian Observatory for Human Rights quoted eyewitnesses in the area as saying they saw jets in the sky at the time of the explosions.

It said the blasts hit Jamraya as well as a nearby ammunition depot. Other activists said a missile brigade and two Republican Guard battalions may also have been targeted in the heavily militarized area just north of Damascus.

Video footage uploaded onto the Internet by activists showed a series of explosions. One lit up the skyline over the city, while another sent up a tower of flames and secondary blasts.

There was no immediate comment from Israeli officials on Sunday’s explosions. “We don’t respond to this kind of report,” an Israeli military spokeswoman told Reuters.

The Jewish state has repeatedly made clear it is prepared to use force to prevent advanced weapons from Syria reaching Lebanon’s Shi’ite Muslim Hezbollah guerrillas, who fought a 34-day war with Israel in 2006. Assad and Hezbollah are allied to Iran, Israel’s arch-enemy.

With Assad battling a more than 2-year-old insurgency, the Israelis also worry that the Sunni Islamist rebels could loot his arsenals and eventually hit the Jewish state, ending four decades of relative cross-border calm.

The U.S. State Department and Pentagon had no immediate comment and the Israeli Embassy in Washington declined comment.

The uprising against Assad began with mainly peaceful protests that were met with force and grew into a bloody civil war in which the United Nations says at least 70,000 people have been killed.

Assad has lost control of large areas of north and eastern Syria, and is battling rebels on the fringes of Damascus.

But his forces have launched counter-offensives in recent weeks against the mainly Sunni Muslim rebels around the capital and near the city of Homs, which links Damascus with the Mediterranean heartland of Assad’s minority Alawite sect.